Endless belt tensioner system and method of use thereof

ABSTRACT

An endless belt tensioner system adapted to dynamically apply a tensioning force on a ground-contacting endless belt of a vehicle is provided, the tensioning force being managed to prevent the endless belt to disengage from an operating configuration when the suspension is actuated. A vehicle and a method of use thereof are also provided.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of, and claims priority under35 U.S.C. 120, to U.S. patent application Ser. No. 12/708,430, filedFeb. 18, 2010, entitled ENDLESS BELT TENSIONER SYSTEM AND METHOD OF USETHEREOF, which is incorporated herein by reference its entirety, andwhich is a non-provisional of, and claims priority under 35 U.S.C.119(e) to, U.S. provisional application No. 61/202,324, entitled ENDLESSBELT TENSIONER SYSTEM AND METHOD THEREOF, filed on Feb. 18, 2009, whichis herein incorporated by reference in its entirety. Any publication ofand any patent issuing from the foregoing U.S. patent applications arehereby incorporated herein by reference.

FIELD OF THE INVENTION

The present application generally relates to an endless belt tensioner.More precisely, the present application relates to an endless belttensioner adapted to change the tension in the endless belt.

BACKGROUND OF THE INVENTION

Vehicles equipped with endless belt drives are adapted to be used onvarious types of grounds. Endless belt drives, or caterpillars, arereplacing, or complementing, weight supporting wheels to reduce groundcontacting pressure and improve floatation and traction on soft grounds.

Each endless belt is generally installed on a set of wheels and/orbearing members supporting and positioning the endless belt on thevehicle. At least one driven tooted wheel, commonly called a sprocket,engages the endless belt to transmit movement to the endless belt andpropel the vehicle. Other optional endless belt supports can also beused to ensure proper operation of the endless belt drive.

The weight-supporting wheels are affixed to a suspension system adaptedto absorb ground imperfections of rugged terrains and provide a smootherride to occupants of the vehicle. A wide-travel suspension systemgenerally allows the passage of significant ground obstacles. However,wide travel suspensions significantly affect the tension of the endlessbelt and increase the risk of disengaging the endless belt from itsdrive sprocket and/or coming off its weight supporting wheels.Significant tension in the endless belt also has an effect on the usefullife of the endless belt.

A need, therefore, exists for an improved tensioner system for theendless belts of all-terrain vehicles.

SUMMARY OF THE INVENTION

The following presents a simplified summary of the invention in order toprovide a basic understanding of some aspects of the invention. Thissummary is not an extensive overview of the invention. It is notintended to identify key/critical elements of the invention or todelineate the scope of the invention. Its sole purpose is to presentsome concepts of the invention in a simplified form as a prelude to themore detailed description of exemplary embodiments, which is presentedlater.

An endless belt tensioner system, and method of use thereof, of thepresent invention (including a kit therefor) may, by way of example, beexploited in relation to an all-terrain vehicle. However, the tensionersystem of the present invention may be used in relation to othervehicles adapted to serve in contexts that differ from the embodimentsdescribed and illustrated hereinafter.

It is to be understood herein that the term all-terrain vehiclegenerally refers to an off-road vehicle although the vehicle couldalternatively be used on the road. It is further understood that theterm endless belt generally refers to a caterpillar-type drive adaptedto impart motive power from the vehicle to the ground by a means thatprovides a wider ground footprint than a wheel. An endless belt, or acaterpillar, can be made of articulated steel parts, rubber, compositematerials (woven material and rubber) or other material suitable to thisend.

Therefore, one object of the present invention improves at least some ofthe deficiencies associated with an endless belt tensioner intended tobe adapted to an all-terrain vehicle.

Another object of the present invention provides an endless belttensioner system that offers a wide travel suspension while assisting inpreventing the endless belt from coming off its proper operatingposition.

An object of the present invention provides an endless belt tensionersystem that offers a wide travel suspension while preventing the endlessbelt from wearing out prematurely.

One object of the present invention provides an endless belt tensionersystem that is hydraulically actuated.

An additional object of the present invention provides an endless belttensioner system that allows high suspension travel thereof.

One additional object of the present invention provides an endless belttensioner system that requires low maintenance and assists in preventingdebris from influencing its useful life.

An additional object of the present invention provides an endless belttensioner system that applies tension to the endless belt proportionalto the traction effort applied to the endless belt.

Another additional object of the present invention provides an endlessbelt tensioner system that applies distinct tension to each of theendless belts in proportion with their respective traction effort.

An additional object of the present invention provides an endless belttensioner system that applies tension to the endless belts when thevehicle moves forward and rearward.

One other additional object of the present invention provides a methodof adjusting tension in endless belts in accordance with behaviors ofthe vehicle.

An aspect of the present invention provides an endless belt tensionersystem that uses a hydraulically actuated tensioner to adjust thetension of the endless belt.

Another aspect of the present invention provides an endless belttensioner system that uses a hydraulic shuttle valve to distributehydraulic pressure to the tensioner system.

One aspect of the present invention provides an endless belt tensionersystem that is, at least in part, disposed on the vehicle in a fashionthat prevents the tensioning system from being contaminated by foreignmaterials.

One other aspect of the present invention provides an endless belttensioner system of which the hydraulic portion is disposed inside theframe and the endless belt contacting wheels are disposed outside theframe and subjected to foreign material.

Another aspect of the present invention provides an endless belttensioner system adapted to be dynamically powered by hydraulicpressure.

One another aspect of the present invention provides an endless belttensioner system provided with a shuttle valve that hydraulicallyactuates the tensioner system when the vehicle moves forward andrearward.

An aspect of the present invention provides a hydraulic endless belttensioner system that uses a drive hydraulic pressure to tense theendless belt.

An aspect of the present invention provides a hydraulic endless belttensioner system for each side of a vehicle, each hydraulic endless belttensioner system being hydraulically coupled with its respectivehydraulic drive system.

One another aspect of the present invention provides a hydraulic endlessbelt tensioner system for each side of a vehicle, each hydraulic endlessbelt tensioner system being hydraulically coupled with the hydraulicdrive system providing the higher pressure therein.

Another aspect of the present invention provides a manually actuatedhydraulic endless belt tensioner system.

One aspect of the present invention provides an automatically pressureregulated hydraulic endless belt tensioner system based, at least inpart, on the traction force, the speed of the vehicle, the steeringangle, the longitudinal inclination of the vehicle and/or thetransversal inclination of the vehicle.

An aspect of the present invention provides a hydraulic endless belttensioner system coupled with a preloading spring providing anon-hydraulic tension preload to the endless belt.

Yet another aspect of the present invention provides, for asubstantially constant hydraulic pressure, a substantially constantendless belt contacting wheels pressure over the endless belt contactingwheels displacement.

One additional aspect of the present invention provides an endless belttensioner system adapted to apply a tensioning force on aground-contacting endless belt of a vehicle, the tensioning force beingsubstantially proportional to an endless belt drive force applied to theendless belt to move the vehicle.

One aspect of the present invention provides an endless belt tensionersystem comprising a tensioner module adapted to physically apply tensionon an endless belt of a vehicle; a vehicle behavior module adapted todetermine the behaviors of the vehicle; and a tensioner managementmodule adapted to position the tensioner module based, at least in part,on outputs provided by the vehicle behavior module.

Another aspect of the present invention provides a vehicle comprising atleast a pair of ground-contacting endless belts each cooperating with atensioning mechanism adapted to determine a tension in theground-contacting endless belt, the tensioning mechanism increasing thetension in the ground-contacting endless belt in function of a speed ofthe vehicle.

Another aspect of the present invention provides a method for managing atension of a ground-contacting endless belt on a vehicle, the methodcomprising sensing the hydraulic pressure in a drive hydraulic systemadapted to propel the vehicle; adjusting the tension in theground-contacting endless belt based at least in part on the sensedhydraulic pressure.

A further aspect of the present specification provides a springmechanism that insures a minimum tension in the endless belt duringvehicle operation and non-operation.

Therefore, in accordance with the present invention, there is providedan endless belt tensioner system adapted to apply a tensioning force ona ground-contacting endless belt of a vehicle, the tensioning forcebeing substantially proportional to an endless belt drive force appliedto the endless belt to move the vehicle.

Also in accordance with the present invention, there is provided anendless belt tensioner system comprising: a tensioner module adapted tophysically apply tension on an endless belt of a vehicle; a vehiclebehavior module adapted to determine the behaviors of the vehicle; and atensioner management module adapted to position the tensioner modulebased, at least in part, on outputs provided by the vehicle behaviormodule.

Further in accordance with the present invention, there is provided avehicle comprising at least a pair of ground-contacting endless beltcooperating with a tensioning mechanism adapted to determine a tensionin the ground-contacting endless belt, the tensioning mechanismincreasing the tension in the ground-contacting endless belt in functionof a speed of the vehicle.

Still further in accordance with the present invention, there isprovided a method for managing a tension of a ground-contacting endlessbelt on a vehicle, the method comprising:

sensing the hydraulic pressure in a drive hydraulic system adapted topropel the vehicle; and

adjusting the tension in the ground-contacting endless belt based atleast in part on the sensed hydraulic pressure.

Other objects, aspects, advantages and features of the present inventionwill become more apparent upon reading of the following non-restrictivedescription of embodiments thereof, given by way of example only withreference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference will now be made to the accompanying drawings, showing by wayof illustration an illustrative embodiment of the present invention, andin which:

FIG. 1 is a front-right isometric view of an all-terrain vehicle;

FIG. 2 is a right side elevation view of the all-terrain vehicle of FIG.1;

FIG. 3 is an isometric view of a tensioner system of the all-terrainvehicle of FIG. 1;

FIG. 4 is an isometric view of the tensioner system of FIG. 3;

FIG. 5 is a rear elevation view of the tensioner system of FIG. 3;

FIG. 6 is an exploded isometric view of the tensioner system of FIG. 3;

FIG. 7 is a side elevation view of the tensioner system of FIG. 3;

FIG. 8 is a transversal cross-sectional view of the tensioner system ofFIG. 7;

FIG. 9 is a schematic side elevation view of the tensioner system ofFIG. 3 and its effect on the endless belt of FIG. 1;

FIG. 10 is a schematic hydraulic circuit illustrating an embodiment ofthe present invention;

FIG. 11 is a schematic hydraulic circuit illustrating an embodiment ofthe present invention;

FIG. 12 is a schematic hydraulic circuit illustrating an embodiment ofthe present invention;

FIG. 13 is an angled view of part of a variant all-terrain vehicle,showing the tensioner system of FIG. 3 provided with a spring mechanism;and

FIG. 14 is a schematic tensioner system comprising three modules,illustrating an embodiment of the present invention.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENT(S) OF THE INVENTION

The present invention will now be described with reference to thedrawings, wherein like reference numerals are used to refer to likeelements throughout. In the following description, for purposes ofexplanation, numerous specific details are set forth in order to providea thorough understanding of the present invention. It may be evident,however, that the present invention may be practiced without thesespecific details.

Thus, an embodiment of the invention is shown on FIGS. 1 and 2 embodiedon an all-terrain vehicle 10. The all-terrain vehicle 10 is constituted,inter alia, of a passenger compartment 20, a frame 30, a drive system40, a power pack 50, a hydraulic system 60, a suspension system 70 and atensioner system 80. The passenger compartment 20 is provided with doors202 pivotally secured on each side of a roof portion 204 via hinges 206,windows 208 disposed on the periphery of the vehicle 10, a back door 212and a plurality of lights 210.

Manufacturing of the passenger compartment 20 of the illustratedembodiment is generally made in aluminum material for reasons ofstrength and weight. Other materials, like steel, plastic or compositematerials, could be used within the scope of the present invention.

The passenger compartment 20 is mounted to the frame 30 thus forming amonocoque construction that enhances the rigidity and the strength ofthe overall vehicle assembly. Most parts of the vehicle assembly can befastened, glued, welded, riveted or secured by other suitable meansknown in the art of vehicle manufacturing.

The power pack 50 is housed in and secured to the frame 30. The powerpack 50 is preferably located low in the frame 30 to keep the center ofgravity of the vehicle 10 as low as possible. Preferably, the power pack50 is transversally centered in the vehicle 10 for reasons of lateralweight distribution. The longitudinal position of the power pack 50 canvary in accordance with the desired mass distribution and volumeallocation. In this respect, the power pack 50 can be disposed in thecenter of the vehicle 10 to advantage mass distribution. Alternatively,the power pack 50 can be positioned toward the rear of the frame 30 toallow maximum room therein for passengers.

An internal combustion engine 502, e.g. a diesel or gas engine, powers ahydraulic system 60 via a rotating or reciprocating hydraulic pump 602.The internal combustion engine 502 could alternatively power more thanone hydraulic system 60 and/or hydraulic pump 602. A plurality ofhydraulic pumps 602 and/or hydraulic system 60 might be desirable forreasons of reliability if the vehicle 10 is expected to be used inextreme conditions by offering redundant systems. More than onehydraulic pump 602 also allows driving independently each endless belt404. The pressurized hydraulic system 60 powers hydraulic motors 406that, in turn, mechanically power the drive system 40 with drivesprockets 402. Intermediate planetary gearboxes (not shown) reduce theratio between each hydraulic motor 406 and its associated sprocket 402.Sprockets 402 of the drive system 40 propel the vehicle 10 by engagingand turning the endless belts 404. Two hydraulic motors 406 areinstalled in the vehicle 10, each moving one of the two endless belts404. The vehicle 10 is steered by a difference in rotation of the twohydraulic motors 406.

Still referring to FIG. 1 and FIG. 2, the suspension system 70 comprisesa plurality of suspension units 702. Each suspension unit 702 uses adouble wishbone configuration 704 coupled on a proximal side to theframe 30 of the vehicle 10 and, on a distal side, to a hub 706. The hub706 pivotally accommodates a tandem 708 to which are rotatably securedsuspension wheels 710. Support wheels 712 are provided on an endlessbelt upper support 714 to maintain the upper side of the endless belt404 on its way toward the front of the vehicle 10.

Tension in each endless belt 404 is independently managed by thetensioner system 80. Endless belt contacting wheels 802 are adapted tomove along the radius generated by tension lever 804 about pivot axis816 to extend or retract the circumference of its associated endlessbelt 404. The tensioner system 80 is adapted to provide proper tensionin the endless belt 404 by dynamically adapting to operating conditionsof the vehicle 10. This aspect of the tensioner mechanism 80 will bediscussed later in more details.

As better seen on FIGS. 3 through 8, it can be appreciated that thetensioner system 80 is actuated by a hydraulic cylinder 806 attached onone side to the frame 30 via an intervening cylinder support 808. Theactuation of the hydraulic cylinder 806 by the hydraulic system 60procures a desired tension to the endless belt 404 (illustrated on FIGS.1 and 2). The hydraulic cylinder 806 is pivotally coupled on the otherside (i.e. piston side), with a rod end 822, to a primary lever 810 thatextends from a pivot member 812. The pivot member 812 is pivotallysecured to the frame 30 by an intervening bearing support 814 adapted toreceive a plurality of ball bearings 824 therein. The two levers 804 areselectively positioned and pivotally secured to the pivot member 812 ata predetermined angle thereto with splines 828 (better seen on FIG. 5)or other means to join both parts while offering angular adjustmentthereof. The angular position of the levers 804 can be changed byremoving the fasteners 826 securing the levers 804 and angularlyrepositioning the levers 804 in the splines 828. Two endless beltscontacting wheels 802 are rotatably secured to a wheel support 818(axle), defining a wheel axis 820 thereabout, abutting the levers 804 oneach end thereof. Each endless belt contacting wheel 802 is providedwith a ball bearing 830 arrangement to facilitate rotational movementsof the endless contacting wheels 802 when the endless belt 404 rotates.

The tensioner system 80 is separated in two portions, the internalportion 840 and the external portion 842. The internal portion 840 isdisposed inside the frame 30 of the vehicle 10 to protect a portion ofthe elements of the tensioner system 80 against dirt, sand, water andother contaminants. In contrast, the external portion 842 extendsoutside the frame 30 of the vehicle 10 and is therefore not protectedagainst contaminants. The junction between the two portions 840 and 842is made with the levers 804 that are extending outside the frame 30 byextending out of the bearing support 814. Levers 804 pivot about thepivot axis 816 to apply tension to the endless belt 404. Sealing of theinterface between the internal portion 840 and the external portion 842is performed with seals 844, which are best seen on FIGS. 6 and 7,disposed on the circular section of the levers 804. In so doing, only aportion of the levers 804 and the endless belt contacting wheels 802 arevulnerable to the environment.

It can be appreciated that the bearing support 814 is sealed to theframe 30 with a series of O-rings 832 installed on each bolt 834securing the bearing support 814 to the frame. A gasket 836 is disposedon the periphery of the bearing support 814 to further seal the bearingsupport 814 to the frame 30.

Alternatively, the internal portion 840 could be defined by a casing(not illustrated) adapted to cover components assembled outside theframe 30. Such an internal portion, despite not being disposed insidethe frame 30 of the vehicle 10 in this alternate embodiment, would besealed from the environment by the casing. Seals 844 could be similarlyinstalled on the levers 804 through the casing thus allowing pivotalmovements of the pivot member 812.

Focusing now on FIG. 7 illustrating the limit positions 850 and 852 ofthe endless belt contacting wheels 802, the tensioner system 80 tensesthe endless belt 404 to the maximum in its extended limit position 850.In contrast, the tensioner system 80, in the retracted limit position852, removes tension in the endless belt 404. A schematic illustrationof an exemplary displacement of the endless belt 404 in accordance withthe limit positions 850 and 852 of the endless belt contacting wheels802 is provided in FIG. 9. It has to be noted that, with the embodiedgeometry, for a constant hydraulic pressure, the force applied by theendless belt contacting wheels 802 on the endless belt 404 remainssubstantially constant over the entire course of the levers 804. This isthat the effective lever of the primary lever 810 and the effectivelever of the levers 804 remains substantially proportional over theentire course of the levers 804.

As mentioned above, one of the objects of the present invention is toprovide sufficient tension in the endless belt 404 to avoid the endlessbelt 404 from any slipperage or coming off with respect to the sprocket402. It also prevents the endless belt 404 from coming off the weightsupporting wheels 710 and the support wheels 712. Significant tension inthe endless belt 404 could be maintained so that no slipperage of theendless belt 404 occurs when driven by the sprocket 402. However, thedown side is that unnecessary tension in the endless belt 404 preventsthe suspension system 70 of the vehicle from working in an optimalfashion. In other words, maximum suspension travel can occur if there issufficient slack in the endless belt 404 to allow the suspension system70 to move. Unnecessary tension in the endless belt 404 restrictsmovements of the suspension system 70 required to provide a smooth ride.

A strategy to avoid any slipperage of the sprocket 402 with the endlessbelt 404 while allowing maximum suspension travel suggests that tensionin the endless belt 404 should be adapted to specific conditions of useof the vehicle 10, namely, inter alia, the drive effort to propel thevehicle 10, the speed of the vehicle 10, the centrifugal force of theturning endless belt 404, vehicle self-pivoting (aka autogiration wheneach endless belt 404 counter-rotate), the steering angle, thelongitudinal angle of the vehicle 10 and the transversal angle of thevehicle 10.

The drive effort to propel the vehicle 10 is provided by the hydraulicsystem 60. By using corresponding hydraulic pressure in the hydraulicsystem 60 used to drive the sprocket 402 tensioner system 80 it ispossible to obtain a correlation between the drive effort provided bythe sprocket 402 and tension of the endless belt 404. Increasedhydraulic pressure in the drive system caused by increased drive effortincreases the tension in the endless belt 404 therefore preventingslipperage of the sprocket 402. In contrast, reduction of the driveeffort reduces the hydraulic pressure in the hydraulic system 60, whichalso reduces the tension in the endless belt 404. The correlation isdynamic and provides corresponding tension in the endless belt 404 atall time. A spring (as seen in FIG. 13, described hereinbelow) isalternatively added to the tensioner system 80 to preload the endlessbelt 404 and provide minimum tension when the hydraulic pressure in thehydraulic system 60 is under a predetermined threshold.

FIG. 10 schematically illustrates a possible embodiment that provides acorrelation between the drive hydraulic pressure and the tension in theendless belt 404. The hydraulic layout of FIG. 10 illustrates a powerpack 50 that actuates the hydraulic pump 602 to hydraulically power thehydraulic motor 406 which, in turn, rotates the sprocket 402 that isengaged to the endless belt 404 to propel the vehicle 10. The hydrauliccylinder 806 of the tensioner mechanism 80 is hydraulically connected tothe hydraulic circuit powering the hydraulic motor 406. This way, thehydraulic cylinder 806 and the hydraulic motor 406 are subjected toidentical hydraulic pressure. This means the hydraulic cylinder 806applies more tension to the endless belt 404 when more drive efforts areprovided to the sprocket 402.

Still on FIG. 10, the forward path 604 of hydraulic oil brings hydraulicpower to the hydraulic motor 406 when the vehicle 10 is propelledforward. Conversely, a rearward path 606 of hydraulic oil bringshydraulic power to the hydraulic motor 406 when the vehicle 10 ispropelled rearward. The hydraulic cylinder 806 is hydraulically poweredfrom both paths 604, 606 of hydraulic oil to tense the endless belt 404when the vehicle 10 is driven in both forward and rearward directions. Ashuttle valve 610 is provided between both paths 604 and 606 ofhydraulic oil to ensure that the hydraulic cylinder 806 is pressurizedby the path 604, 606 providing the highest hydraulic pressure whetherthe vehicle 10 is driven forward or rearward. Additional informationabout an exemplary shuttle valve 610 suitable to be used in the presentembodiment is available at Annex 1 and incorporated herein by reference.

FIG. 11 illustrates a hydraulic layout having two distinct hydrauliccircuits, i.e. one hydraulic circuit 612 for driving the endless belt404 disposed on the left side of the vehicle 10 and another 614 for theendless belt 404 disposed on the right side of the vehicle 10. Eachhydraulic circuit 612, 614 is pressurized by the same power source 50(although more than one power source 50 could be used without departingfrom the scope of the present invention) activating distinct hydraulicpumps 602.1 and 602.2. One hydraulic pump for each hydraulic circuit612, 614 ensures that enough hydraulic pressure is provided to eachhydraulic motor 406.1, 406.2. The quantity and the pressure of hydraulicfluid in each hydraulic circuit 612, 614 varies in accordance with thedrive effort (hydraulic fluid pressure), the speed of the vehicle 10(hydraulic fluid velocity), the load of the vehicle 10 and, inter alia,the steering angle if the vehicle 10 turns. Shuttle valves 610.1 and610.2 are provided in each hydraulic circuit 612 and 614 between thehydraulic lines 604, 606 to achieve the same purpose as described abovein respect to FIG. 10. Therefore, each hydraulic cylinder 806 will berespectively actuated by the hydraulic circuit 612 or 614 that drivesits associated endless belt 404. Moreover, the highest hydraulicpressure will still be used by each hydraulic path 604, 606 when theendless belts 404 moves either forwardly or rearwardly.

Referring now to FIG. 12 illustrating the hydraulic system of FIG. 11with an additional shuttle valve 610.3. The shuttle valve 610.3 isprovided between both hydraulic circuits 612, 614 to equally use theabsolute highest hydraulic pressure simultaneously on both hydrauliccylinders 806.1, 806.2.

Annex 2, enclosed herein and incorporated by reference, providestechnical information about a hydraulic proportional pressure reducingvalve that can optionally be used in the hydraulic system of the vehicle10. The proportional valve can alternately be used to replace theshuttle valve 610 and provide only the desired amount of pressure toeach hydraulic cylinder 806. The proportional valve is adapted toreceive an electric signal about a desired output pressure, if theoutput pressure is different than the electric signal the proportionalvalve adjusts the output pressure until it reaches the desired outputpressure. Alternatively, a pilot pressure could be used by theproportional valve to determine the amount of pressure that reaches eachhydraulic cylinder 806 through the hydraulic proportional valve. Thepilot pressure can be managed by controllers adapted to manage hydraulicsystems as exemplified in Annex 3 a and Annex 3 b, both incorporatedherein by reference.

With reference to FIG. 13, a spring mechanism 90 has been added to eachabove-described tensioner system 80 to ensure a minimum tension on theendless belt 404 during operation and non operation. The springmechanism 90 herein includes a pair pneumatic springs 902, which arecompressed between the frame 30 and a component 904 (for instance, thepiston end of the hydraulic cylinder 806) that is connected to themechanism that cause the tension levers 804 to pivot. Therefore, thesprings 902 exert pressure in direction 906 onto the component 904,which in turn forces the tension levers 804 along direction 908 therebybiasing the contacting wheels 802 against the endless belt 404. Thespring mechanism 90 is thus exemplarily herein coupled with thehydraulic cylinder 806 through the rod end 822 secured to the primarylever 810. Other types of springs can be used instead of the presentpneumatic springs 902.

FIG. 14 illustrates a tensioner system comprising three modules. Thetensioner system 80 of FIG. 14 is a constituent of a vehicle 10, asillustrated in FIG. 1 and FIG. 2. The vehicle 10 further includes atleast one endless belt 404, as illustrated in FIG. 1 and FIG. 2. Thetensioner system 80 of FIG. 14 comprises a vehicle behavior module 882,a tensioner management module 884, and a tensioner module 880. Thevehicle behavior module 882 determines the behaviors of the vehicle 10.The tensioner management module 884 positions the tensioner module 880,based, at least in part, on outputs provided by the vehicle behaviormodule 882. And the tensioner module 880 physically applies tension onthe endless belt 404.

The description and the drawings that are presented herein are meant tobe illustrative of the present invention. They are not meant to belimiting of the scope of the present invention. Modifications to theembodiments described may be made without departing from the presentinvention, the scope of which is defined by the following claims:

What is claimed is:
 1. An endless belt tensioner system comprising: atensioner module adapted to physically apply tension to an endless beltof a vehicle; and a tensioner management module adapted to manage thetensioner module, wherein the endless belt tensioner system dynamicallymanages the tension in the endless belt to allow appropriate suspensionmovement and to prevent the endless belt to disengage from an operatingconfiguration when the suspension is actuated.
 2. The endless belt ofclaim 1, wherein the tension in the endless belt is based at least inpart on the speed of the vehicle.
 3. The endless belt of claim 1,wherein the tensioner module includes an hydraulic cylinder actuatableto manage the tension in the endless belt, the hydraulic cylinder beingadapted to be operatively located outside a periphery of the endlessbelt.
 4. The endless belt of claim 3, wherein the tensioner moduleincludes at least one lever operatively connected between the hydrauliccylinder and at least one endless belt contacting wheel adapted to beoperatively disposed within the periphery of the endless belt.
 5. Theendless belt of claim 1, wherein the tensioner module is adapted toindividually manage tension in two separate endless belts operativelysuspending the vehicle.
 6. The endless belt of claim 1, wherein, whenthe endless belt tensioner system is installed on a vehicle, the tensionin the endless belt is adapted to be substantially proportional to anendless belt drive force propelling the vehicle.
 7. The endless belt ofclaim 1, wherein, when the endless belt tensioner system is installed onthe vehicle, the tension in the endless belt is adapted to be managed bythe tensioner module when the vehicle moves forward and when the vehiclemoves rearward.
 8. A vehicle including an endless belt tensioner system,the endless belt tensioner system comprising: a tensioner module adaptedto physically apply tension to an endless belt of a vehicle; and atensioner management module adapted to manage the tensioner module,wherein the endless belt tensioner system dynamically manages thetension in the endless belt to allow appropriate suspension movement andto prevent the endless belt to disengage from an operating configurationwhen the suspension is actuated.
 9. The vehicle of claim 8, wherein thetension in the endless belt is based at least in part on the speed ofthe vehicle.
 10. The vehicle of claim 8, wherein the tensioner moduleincludes a hydraulic cylinder actuatable to manage the tension in theendless belt, the hydraulic cylinder being adapted to be operativelylocated outside a periphery of the endless belt.
 11. The vehicle ofclaim 10, wherein the tensioner module includes at least one leveroperatively connected between the hydraulic cylinder and at least oneendless belt contacting wheel adapted to be operatively disposed withinthe periphery of the endless belt.
 12. The vehicle of claim 8, whereinthe tensioner module is adapted to individually manage tension in twoseparate endless belts operatively suspending the vehicle.
 13. Thevehicle of claim 8, wherein, when the endless belt tensioner system isinstalled on a vehicle, the tension in the endless belt is adapted to besubstantially proportional to an endless belt drive force propelling thevehicle.
 14. The vehicle of claim 8, wherein, when the endless belttensioner system is installed on a vehicle, the tension in the endlessbelt is adapted to be managed by the tensioner module when the vehiclemoves forward and when the vehicle moves rearward.
 15. A method ofmanaging a ground-contacting endless belt tension installed on avehicle, the method comprising: sensing a vehicle behavior; anddynamically adjusting the tension in the ground-contacting endless beltbased, at least in part, on the sensed vehicle behavior while allowingsufficient slack in the endless belt so as to allow appropriatesuspension movement and to prevent disengagement of the endless beltfrom its operating configuration on the vehicle.
 16. The method of claim15 wherein the appropriate suspension movement corresponds to allowingmaximum suspension travel.
 17. The method of claim 15, wherein adjustingtension in the ground-contacting endless belt is made on a basis of anactuation of a hydraulic cylinder disposed outside a periphery of theground-contacting endless belt.
 18. The method of claim 17, wherein theactuation of the hydraulic cylinder further actuates at least one leveroperatively connected between the hydraulic cylinder and at least oneendless belt contacting wheel adapted to be operatively disposed withinthe periphery of the endless belt.
 19. The method of claim 17, furthersensing a drive direction of the vehicle.
 20. The method of claim 17,further separately adjusting the tension in a plurality ofground-contacting endless belts on the vehicle.